The present invention relates to a switch device provided with an operating knob operable to select among among an automatic neutral-point restoring position and an automatic nonneutral point locking position according to an operational amount thereof.
Conventionally, a switch device employed as an opening/closing switch for an automotive power window is known, which device is provided with an operating knob operable to select among an automatic neutral-point restoring position and an automatic nonneutral point locking position according to an operational amount thereof. Such a switch device is disclosed in Japanese Utility Model Laid-Open Publication No. 56-22736.
An example of this kind of known switch device is shown in FIGS. 9 and 10. FIGS. 9 and 10 are a sectional side view and a sectional bottom view of the conventional switch device, respectively. The switch device comprises a case-like switch body 51, an operating knob 52, a selector member 53 to be driven by the operating knob 52, a contact portion 54 to be switched on and off by the selector member 53, and a solenoid 55 for maintaining the selector member 53 in a fixed position.
As shown in FIG. 9, the operating knob 52 has a substantially T-shaped configuration. A vertical member 52a of the operating knob 52 is formed at its side surface with pivots 56 horizontally projecting therefrom, so that the operating knob 52 is pivotably mounted to the switch body 51. The vertical member 52a is formed with an axial hole opened at its lower end for receiving a spring member 57 and a pin 58. The pin 58 is vertically downwardly biased by the spring member 57. The switch body 51 is formed with a substantially V-shaped plate 59 against which the pin 58 abuts resiliently. In a horizontal position (which will be hereinafter referred to as a neutral position) of the operating knob 52, the pin 58 abuts against a bottom portion 59a of the substantially V-shaped plate 59. When the operating knob 52 is operated by an operator to be rocked clockwise and counterclockwise, and the pin 58 is slid along the substantially V-shaped plate 59 beyond an angular portion 59b of the plate 59, the operator can feel clicking.
The selector member 53 is provided with a connecting pin 60 to be integrally connected to a lower end portion of the operating knob 52. Accordingly, when the operating knob 52 is depressed at its right end to be rocked clockwise from the neutral position, the selector member 53 is moved leftwardly in interlocking relationship with the operating knob 52. In contrast, when the operating knob 52 is depressed at its left end to be rocked counterclockwise from the neutral position, the selector member 53 is moved rightwardly in interlocking relationship with the operating knob 52.
Movable contacts 61a and 61b of the contact portion 54 are mounted on opposite ends of the selector member 53. In the neutral position of the operating knob 52, the movable contacts 61a and 61b are electrically connected with a first fixed contact 62. In association with the movement of the selector member 53, the movable contacts are selectively brought into electrical connection with a second fixed contact 63.
A pair of plunger retainer arms 53a extend from the opposite ends of the selector member 53 for retaining a plunger 55a of the solenoid 55. In the neutral position of the operating knob 52, a body of the solenoid 55 is located at a central position of the plunger 55a, and is fixed to the switch body 51.
In operation, when the operating knob 52 is operated to move the selector member 53 rightwardly or leftwardly, the movable contacts 61a and 61b are selectively brought into electrical connection with the fixed contacts 62 and 63. In the case that the operating knob 52 is depressed within an operating range where the pin 58 contacts a slant surface of the substantially V-shaped plate 59, when the depressed force is removed, the selector member 53 is automatically returned to the neutral position by an elastic force of the movable contacts 61a and 61b or the like. In the case that the operating knob 52 is depressed until the pin 58 moves beyond the angular portion 59b of the substantially V-shaped plate 59, the solenoid 55 is excited to automatically lock the plunger 55a and the selector member 53 in this position. Accordingly, even when the depression force is removed, the contacts are maintained in the on-state.
Accordingly, when the switch device is applied to an opening/closing switch for an automotive power window, for example, the window may be opened or closed by a desired amount by operating the operating knob 52 under the automatic neutral-point restoring condition, and the opening/closing operation of the window may be automatically stopped by releasing the manual operation of the operating knob 52. The operator need not manually restore the operating knob 52 to the neutral position under this position. Further, the window may be automatically opened or closed to a full open or full closed position by operating the operating knob 52 to the automatic nonneutral point locking position. In this condition, the operator does not need to continue to press the operating knob 52 until the window reaches the full open or closed position. Solenoid 55 holds the switch in the nonneutral position until the window is fully opened or closed and then releases the switch, allowing it to automatically restore itself to the neutral position.
However, in the above-mentioned conventional switch device, when the operating knob 52 is operated to the automatic nonneutral point locking position, the solenoid 55 continues to be excited until the automatic locking condition is released, so as to maintain the automatic locking condition. Therefore, power consumption is increased, and heat generation is also increased, which is a most important problem in an on-vehicle electrical equipment.